1. Field of the Invention
This invention relates to optical sensing of labels on rotating labeled containers.
2. Description of the Prior Art
As an adjunct in consideration of the predication of the present invention, consider various well-known practices for the packaging and display of beverage bottles and cans, such as for soft drinks and beer. As is known, beverage bottles and cans are frequently marketed in cluster packages, such as the well-known six-pack, and the emerging two-pack of larger containers. The well-known six-pack may be a cardboard wrap, in whch the ends are open; or it may be High-cone (TM), in which cans are held together by a thin molded network of soft plastic; or in a clear wrap, in which the containes are wrapped in a plastic which is then shrunk so as to grip them. In the latter two cases, there is no labeling of the cluster package, other than labeling on the individual containers therein; in the case of the cardboard wrap, cluster package labeling appears from a side view, but end view labeling is limited to the labeling on the individual containers. Quite obviously, since most round container labels (particularly bonded paper labels) cover only 120.degree. of the container periphery, there is a more than 50 percent chance that full product identification will not be readable on at least some of the containers when the cluster package is disposed on a shelf for viewing by consumers. It is, therefore, desirable and advantageous to rotate the containers before assemblage in the cluster package to ensure that any container labels which are to be used for product identification while on the display shelf are rotated in such a fashion that the labels bearing product identification will be clearly visible to the consumer.
When orienting labels, the containers may be preclustered on the packaging machine and may be rotated the desired amount prior to arriving at the first packaging station. The containers should be viewed in some fashion while being rotated, and the rotation ceased when the viewing apparatus detects that the package is in the proper position. The techniques of gripping and rotating containers have been well known for many years in the package handling arts. However, the technology of viewing and of processing the resulting signals has heretofore left much to be desired. For instance, the technology for utilizing normal white light, which thereby permits the use of relatively inexpensive and highly available television-type equipment, is most advantageous; on the other hand, optical considerations--such as reflections from minor flaws, changes in ambient light as a result of surrounding procedures, transients from many different sources and the like--create difficulties in producing signals in response to ordinary white light. Additionally, the economics of beverage packaging are extremely critical; although a single bottle, can or other container may be processed at one time or a single cluster (such as a six-pack) may be processed at one time, the cost of such processing relative to the production rate of packaging of six-packs and the like may be prohibitive, since the containers must be packaged at a rate commensurate with the rate of other processing on an automated line. The on-line sensing must be powerful enough to avoid reducing production rates below those which are permissible, and to avoid the need of several computers or other signal processors.
In the container handling arts, apparatus is known which rotates containers, such as bottles and cans, and stops them in the desired position, either to check label registration (whether they be bonded paper labels or painted labels), or for other purposes. However, in such systems known to the art there is usually required a special sensing mark of some sort on the container, and most such devices are capable of orienting only one container at a time. Obviously, a multiplicity of such devices would be required in the event of usage with an assembly line which processes a large number of bottles in parallel at one time.
Additionally, in the event that cluster packaging is involved, it is difficult to process a single container at a time since there is a need to have the containers arranged in clusters as well as being properly oriented at the time of packaging. When complex electronic equipment is involved, it is desirable to utilize the electronic equipment for as many containers in one processing batch as possible, to minimize the amount of equipment required in order to process sufficient containers at the processing rate of the overall system. In some systems, the processing of the containers is already provided for, and the orienting equipment is to be added thereto as a retrofit. In some of these systems, the clusters of containers (such as six-packs) may be processed broadside, that is, with the long side of the cluster (or six-pack) arranged in the forward and aft direction and the short sides facing laterally of the processing line. This presents additional difficulties to optical sensing equipment since the two center containers in a six-pack (for instance) are not available at the edges of the production line, and must be accommodated in a special fashion.